The researchers said they had observed this behavior seven times over an eight-day period in 2011. They believe the relationship between the whales and dolphin has been a purely social one.

According to the report, the dolphin's condition made it an outcast to its pod, giving it a "low social status," prompting it to seek the company of the whales.

"It really looked like they had accepted the dolphin for whatever reason," Alexander Wilson, an ecologist who was snorkeling nearby, told Science Magazine. "They were being very sociable."

He said sometimes individuals in the pod could be picked on, so it may be that this particular dolphin didn't fit in with its own kind.

Wilson says this discovery shows sperm whales have a capacity for these types of relationships, implying they may sometimes benefit from them. Not only is the relationship odd, but cetacean ecologist MÃ³nica Almeida e Silva of the University of the Azores in Portugal pointed out the two species do not have a good history with one another.

She told Science Magazine she has often seen bottlenose dolphins chasing and harassing whales and their calves.

"Why would sperm whales accept this animal in their group?" she told the magazine. "It's really puzzling to me."

Although unorthodox, this behavior is not the first time scientists have witnessed dolphins and whales getting along in this capacity. In 2008, a bottlenose dolphin known for playing with humans led two beached pygmy sperm whales back to safety after responding to their calls for help.